Process for reclaiming used lubricating oil



June 9, 1936. N E 2,043,691

PROCESS FOR RECLAIMING USED LUBRICATING OIL Filed May 14, 1951 (T-"7 l i 'r I I I i l 5 I ii i 2 5 E I I l H 1 nHP-W Patented June 9, 1936 PATENT OFFIE PROCESS FOR RECLAIMING USED LUBRICATING OIL Frederick G. Baender, Corvallis, Oreg.

Application May 14, 1931, Serial No. 537,341

4 Claims.

This invention relates generally to the reclamation of used lubricating oil, and particularly to process, in which a rotatable still is employed in order to heat the oil to a sufficient temperature and maintain a sufiiciently high pressure to prevent vaporization of the components below the lubricating base, but to insure the vaporization of the lighter components, as well as the moisture which is usually emulsified with the used lubricating oil.

It is well-known that lubricating oil after it has been used, such as, for instance, in an internal combustion engine, is rendered useless for lubricating purposes not by reason of the destruction of its lubricating properties, but for the reason that so much foreign matter has become accumulated in it and water and gasolinepor other light petroleum components have become mixed with it during its use to such an extent that further use of the lubricating oil is more injurious than beneficial to the moving parts of the engine. Many efforts have been made to devise a process and apparatus which would be suitable for reclaiming such used lubricating oil, but the reclaimed oils produced by the processes heretofore known have not as a general rule been favorably received by the public, principally for the reason that the color thereof is not acceptable but is so dark as compared with first run lubricating oil that the impression made upon the layman is unfavorable. Diificulty has also been experienced in removing the lighter components, as well as moisture, from such a used lubricating oil.

In the processes which have been heretofore employed in refining or reclaiming oils, in which a substantial quantity of moisture is entrained, it has been necessary to expel the entrained moisture from the body of the oil extremely slowly in order to prevent so-called vomiting which is the mechanical carrying oif of the oil by the vapors. In accordance with the prior processes, when the oil is rapidly heated to expel the moisture, the vaporization of the moisture entrained in the oil-creates such a disturbance therein that a substantial quantity of the oil is in fact carried cfif by the vapors. If, however, the heating is carried out slowly and the moisture released slowly therefrom, this disadvantageous expelling of the oil by the vapors is usually avoided. It is among the objects of this invention, however, to provide a process and apparatus bywhich a body of oil may be rapidly heated and the entrained moisture therein rapidly expelled without the loss of any substantial portion of the oil during vaporization of the moisture.

It is accordingly an object of this invention to provide a process of reclaiming used lubricating oil in which the disadvantageous features of the processes heretofore known are overcome.

A more specific object of this invention is to provide a process of reclaiming used lubricating oil in which the distillation is carried out at a high temperature but under sufiicient pressure to prevent cracking of the lower components.

Another object of this invention is to provide a process by which a reclaimed lubricating oil of natural color is produced.

Another object of this invention is to provide a process by which the oil to be reclaimed is heated to a comparatively high temperature in a comparatively short time.

A further object of this invention is to provide a rotatable still suitable for use in the reclamation of used lubricating oil.

A more specific object of this invention is to provide an automatically controlled device for periodically releasing vapors from a rotatable still.

Other objects will become apparent to those skilled in the art when the following description is read in connection with the accompanying drawing, in which: Figure 1 is a view somewhat diagrammatic in form and illustrating particularly the novel rotatable still constructed in accordance with this invention;

Figure 2 is a detail view of a suitable driving device of the still illustrated in Figure 1; and

Figure 3 is a detail view of a cam for cooperation with the release valve on the still.

In accordance with this invention, lubricating oil, which has been previously used and which is to be reclaimed by the process of this invention, is initially given an acid treatment for the purpose of breaking the emulsified condition of the used lubricating oil and precipitating the foreign matter carried thereby. After the acid treatment, the oil under treatment is allowed to set for a sufficient time to permit the precipitant to settle out in the form of sludge. After the sludge has settled out, the body of the oil is then preferably neutralized with any suitable basic substance, such as, for instance, lime, and a quantity of fullers earth is then added and the mixture agitated until the fullers earth and lime are substantially uniformly distributed throughout the body of the oil. This mixture is then preferably introduced into a suitable still, such as, for instance, the improved rotatable still to be hereinafter more fully described, and heated to a sufficient temperature and under a controlled pressure so that the water vapors are first driven off, after which the temperature may be sufficiently raised and the pressure so controlled that the lighter volatiles, which have become mixed with the lubricating oil, are successively driven off, and if it is desired to produce a heavy oil, the temperature may be sufficiently raised so that a cut of light lubricant is taken. In accordance with this invention, after as many of the components as is desired. have been vaporized, the remaining unvaporized oil with the mixture of fullers earth is then cooled and filtered to remove the fullers earth and chemicals from the oil, and it has been found by such process the reclaimed lubricant is of natural color and possesses other lubricating properties of. the same character as a first run lubricating oil would have.

Referring now to the drawing, and particularly to Figure 1, the used lubricating oil to be treated may be placed ina tank I, which is preferably formed in the nature of: a hopper having at the bottom thereof a Valve 2; A quantity of sulphuric acid is then added to the oil in the-tank I, the quantity being governed by the nature of the oil and the amount of impurities which are entrained therein. Under ordinary circumstances, an operator may by close observation and after a few trials readily predetermine the amount of acid which may be necessary for treating a particular oil simply by'the feel of the oil.

An air compressor 3 is provided and has a reservoir 4' connected by means of a pipe 5 with the tank I. The pipe 5 extends downwardly into the tank l to a positionvery near the bottom thereof. After the sulphuric acid has been added to the oil in the tank a valve 6 may be released to permit the escape of compressed air from the reservoir 4 through the pipe 5 to the tank I. The escaping compressed air from thepipe 5 within the tank I agitates the mixture of' used oil and sulphuric acid so that the acid i'sthoroughly distributed-throughout the oil, thus'permitting the acid to react with the impurities present and precipitate them. After the oil and acid have been sufliciently agitated, the valve 6 maybe closed to discontinue the supply of compressed air through the pipe 5; and the mixture in the tank I is permitted to set for a sumcient time to permit the precipitant to settle out as a sludge in the bottom-of the tank; After the precipitant has settled out, the valve 2 may be opened to permit the escape of the-sludge from the bottom of the tank Any suitable receptacle, such as 1', may be provided beneath the valve Zforreceiving the sludge. An operator will readily be able to determine when all the sludge has been removed, since the differences in appearance between the sludge and treated oilwill be apparent even to one unskilledin the art. After the sludge has been withdrawn, the valve 2is closedso that the oil remaining in the tank i has had practically all its solid impurities removed and the emulsion substantially broken.

A quantity of lime or any suitable basic substance is then added to the oil in the tank 5, and preferably at the same time a quantity of 'fullers earth is added thereto. The valve 6 may then be again opened to release the compressed air into the tank I and thoroughly agitate the mixture therein to distribute the fullers earth: and lime throughout the body of'the oil; After the mixture of oil, fullers earth and lime has been sufiicientlyagitated; the mixture is then readyto be heated in the novel still'constructed' in accordance with this invention for removing the fractions not suited for lubricating purposes.

The still constructed in accordance with this invention is preferably of a rotatable type and in the embodiment illustrated in the drawing comprises a drum 8 mounted upon an axle 9. Suitable bearings in may be provided at the opposite ends of the axle 9 and are supported by a suitable frame strucltureisuch as, for instance, the uprights H.

The uprights H are joined at their upper ends by a plurality of horizontal members I2. A fire chamber l3 having a stack i4 is provided surrounding'the drum 8 and is supported at one end by a strap, such as 15, from the horizontal members 12; it being understood that the straps l 5 are preferably provided in duplicate, one being on eachsideof' the chamber I3. In the embodiment illustrated in the drawing, a suitable plate or beam i6 extends across the bottom of the chamber l3 andis connected at one end thereof to uprights H and at the other end thereof to straps l5, so that the chamber l3'is supported by the frame structure uponwhich the drum 8' is journaled: The chamber l3is preferably provided withacover of insulating material, such as I1, and may be provided on the interior thereof with a suitable heating-device, such as; for instance, an oilburner l 8 preferably disposed directly beneath the drum 8, and in heating relation thereto. From thestructure just described, it is apparent that a supply of fuel oil may be burned atthe burner i8'-to heat the drum 8 and the oil contained therein, the gases of combustion being permitted-to escape from the chamber [3 through the stack i4.

As pointed out above, the drum 8-is rotatably mounted relative to the supporting-structure and to the chamber l3, and in accordance with this invention, the-drum is preferably rotated during the application of heat thereto. The drum 8 is preferably provided on the interior thereof with a plurality of axially extendingangle irons, such as l9, havingthe flanges thereof extending radially on-the-interior of the drum. It is apparent that the angle irons l9 will operate to agitate-the mixture within the drum during the rotation thereof, and, furthermore, the'fianges' of the angle'irons IQ serve the useful function of conducting heat from thesurface'of the drum up inwardly into the body of the mixture contained therein.

In the embodiment shown in the drawing, the axle 9 is preferably hollow at one end thereof, being provided with a central opening 2! therethrough for a short distance, but it will be understood that the central opening 2! preferably terminates externally ofthe-drum 8. A suitable conduit 22 is provided in communication with the opening 2! near the inner extremity thereof, and at its other endthe conduit 22'is connected with the housing of a valve 23; tobe more fully describedhereinafter.

At its outer end the axle 9 leads into a condenser 24, which may be of any suitable type well-known in the art, and the central opening 2| is connected to the usual coil of the condenser 24, whereby vapors released from the drum 8 through the valve 23 may be conducted through the conduit 22 and the opening 2| to the condenser24;

The drum 8 is also provided with a valve 25,

which is preferably disposed for connection, when in the position-shown in Figure 1, with the conduit 25 leading toa cooling chamber 21 of any suitable type. The valve 25 is also preferably so disposed that it may be connected with a conduit 28 leading from tank I when in'itsuppermost position, 180 displaced from the position illustrated in Figure 1. The conduits 26 and28 are, respectively, provided :with suitable union connections, such as 29 and 30, for connection with the valve 25 when properly positioned.

The drum 8 may also be provided with a pressure indicating device 3| of any suitable type, as well as a pyrometer 32 for indicating the temperature of the mixture within the drum.

The valve 23 is provided for periodically releasing the vapors which are driven oil the mixture within the drum 8 during the heating thereof, and in the illustrated embodiment, comprises a valve element 33 having a stem 34. A spring 35 is preferably provided for biasing the valve element 33 into its seated position wherein the valve is closed, and at the outer end thereof the stem 34 is provided with a head 36 for engagement with a cam 31 during movement of the drum 8. The cam 31 is preferably mounted upon the supporting structure for the drum and is so disposed that the head 36 of the valve 23 will be moved against it to actuate the valve into its open position whereby to permit release of the vapors in the drum 8 during the time in which the head 36 is in contact with the cam 31.

Since the occasion often arises, and especially during preliminary heating of the mixture within the drum 8, when it is not desired to periodically release the valve 33, but to permit the pressure to build up within the drum during the heating and expansion of the mixture therewithin, and, accordingly, it is preferable to provide the cam 31 with a device whereby it may be moved out of the position in which it engages the head 36 of the valve 23. A suitable embodiment of such a cam is illustrated in detail in Figure 3, wherein a suitable supporting structure, such as plate 38, may be suitably mounted upon the frame structure supporting the drum 8 and chamber l3, and thus held in stationary position relative to the movable parts. A strip of spring steel 39, which is, in fact, the camsurface of the organization, may be mounted at one end thereof by any suitable device such as a rivet upon the plate 38. At its opposite end, the strip 39 maybe slotted to receive a rivet or pin 4| in slidable relation thereto. Intermediate the rivets 40 and 4|, the plate 38 is provided with a threaded part 42 disposed to receive a screw 43. As clearly illustrated in Figure 3, the end 44 of the screw, 43 is disposed to engage the strip 39 and thereby force the strip outwardly away from the plate 38 for a sufficient distance to bring the strip 39 into the path of head 36 of valve 23 during the movement of the drum. It is thus apparent that when the screw 43 is so turned as to move the end 44 thereof toward the right, as seen in Figure 3, the strip 39 will collapse or straighten out into substantial alinement with the plate 38, thereby bringing the cam surface thereof into such position that it will not be engaged by the head 36 during the movement of the drum 8.

A suitable driving mechanism for the rotatable drum 8 is illustrated in Figure 2, and. in the illustrated embodiment, the driving mechanism is disposed to oscillate the drum or move the same alternately in opposite directions through an angle slightly in excess of a full circumference, or approaching 370. The driving mechanism shown in Figure 2, may be driven by any suitable device, such as, for instance, an electric motor 45, which has mounted on the outer end of the shaft thereof a crank arm 46. A segment 41 is pivot'ally mounted at 48 upon the supporting structure including the upright members H, and is provided along its periphery with a plurality of gear teeth 49 disposed to engage the teeth of pinion 50 mounted upon axle 9 of the drum 8. A pitman rod 5|, or any other suitable device, may be provided for connecting the crank arm 46 with the segment 41 whereby the segment 41 will be oscillated about its pivot 48 upon each revolution of the arm 46. In the embodiment illustrated in the drawing, the lengths of the respective crank arms at 46 and 41 are preferably so proportioned that upon each revolution of the arm 46, the segment 41 will be moved in each direction for an angular distance suflicient to rotate the pinion 50 for substantially 370 in.

each direction. In the position illustrated in Figure 2, the mechanism is disposed at an intermediate position in which the drum 8 occupies a position 180 displaced from that illustrated in Figure 1. With a driving mechanism, such as that just described, it is apparent that the drum 8 will be oscillated, upon each revolution of the arm 46, through an angle slightly in excess of a full circumference and approaching 370 whereby the head 35 of the valve 23 will be brought into position adjacent the cam 31 at the end of its movement in each direction, that is, twice during a single revolution of the arm 46; it being understood that when the valve 23 is in the position illustrated in Figure 1, then the teeth 49 of the segment 41, near one end or the other thereof, will be in engagement with the teeth of the pinion 53; Moreover, with an arrangement of this sort, it is apparent that the valve 23 will be maintained in its open position for a period of time substantially twice the period of time which the cam 31 would maintain it in its open position if the drum 8 were rotated in but one direction, and although the mechanism illustrated in the drawing is preferable under some conditions of operation, it is to be distinctly understood that any suitable driving mechanism for either oscillating or rotating the drum in a single direction may be employed in lieu of that shown. With the mechanism of the illustrated embodiment, however, agitation of the mixture contained within the drum is under most circumstances more thorough than when the drum is rotated in but a single direction.

The cooler 21 may be of any suitable type for substantially reducing the temperature of the mixture of oil and fullers earth, which is withdrawn from the drum 8 after the desired components have been vaporized. A conduit 52 is provided for conducting the cooled mixture from the cooler 21 to asuitable pump 53. The pump 53 forces the mixture from the cooler 21 through a conduit 54 to a filter press 55. The filter press 55 may be of any suitable type Well-known in the art, such as, for instance, the so-called bag filter, wherein a plurality of bags, in this instance five, are suspended within the chamber, and the mixture under the force exerted by pump 53 is forced through the bags; it being understood that the fullers earth and chemicals remain on the outside of the bags while the oil is forced through the layer of fullers earth on the outside of the bag and into the outlets 56 for the respective bags, eventually reaching a conduit 51. The conduit 51 conducts the reclaimed lubricant to any suitable storage container (not shown).

In the operation of the apparatus hereinbefore described, the used lubricating oil, after being acid treated and. neutralized as well as having a hereinbefore been-described, is transferred to the, drum" 8'. When, it is desired to fill the drum 8, thedrum may be moved into, the position illustrated in Figure 2', where-the valve 25 is disposed in itsuppermost position and adjacent the union 38 oncthe'conduit28; The union 30 is then connected;with the threaded part on, the valve 25 and a, valve 58 in conduit 28 opened to permit the oil from tank I to flow into the drum 8. Whena suflicient quantity'of lubricant has been released into the drum 8, the valve 58 may then be shut off, the union 30' disconnected and the valve 25 closed to prevent the escape of oil from the'drum 8. The burner I8 may then be ignited andmovement of the drum 8 begun. It will be understood that during the time in which the oil, within the drum 8 is being heated, the drum 8: is; being continually oscillated,,as hereinbefore described, and since it is desirable to permit the pressure Within the-drum to build up, the screw 43' will be released to bring the spring strip 39 into a positioncin which it will not be operative to open the valve2-3 during movement of the drum.

The temperature of the oil within the drum is then raised sufficiently. to vaporize the moisture which had been adsorbed by the fullers earth, it being understood that when the fullers earth is initially mixed with the oil in tank l, the moisture entrained therewithin will become readily adsorbed by the fullers earth, but when the mixture of oil and fullers earth is suifioiently heated within the drum 8, the moisture will be vaporized and rise to the top of the drum. Under-ordinary circumstancescit is desirable to increase the temperature to about 350 F. where a pressure of approximately 120 pounds per square inch will be present withinthe drum before the valve 23 is first opened to permit the escape of the steam. It is important at this stage of the operation that the temperature sufficient to vaporize the moisture be maintained for a timesuiilcientto vaporize all the moisture entrained in the body of oil before any of the vapors are released. In accordance with this invention the heating: of the-coil is carried on rapidly so that vaporization of the moisture entrained therein takes place with exceeding rapidity, but all the vapors are confined within the drum 8untilthe vaporization is completed and the boiling has ceased. It is well-known that when entrainedmoisture in a body of'oil is permitted to vaporize rapidly, a substantial quantity of the oil is carried oil by the vapors, but in accordance with this invention, the vapors are collected above the surface of the oil until the vaporization of moisture therein has been concluded, so that the oil which is carried oil by the vapors may fall back into the body of the oil while the vapors are collected above the surface thereof and in the'drum. 8. In accordance with this invention, none of the vapors are released until after all the moisture has been vaporized so that none of the heavy oil is mechanically dispelled out of the drum with the vapors. Accordingly, when the desired temperature and pressure has been reached atwhich the moisture is all vaporized and present above the surface of the oil as steam, the screw 43 maybe actuated to bring the spring-strip 39 into position for engagement with the head 36 whereupon, during the movement ofthe drum 8, when the head36 comes into engagement with the cam 31, the valve 33 will be forced inwardly against the ac- 2,043,691: quantity; of fullers-earth mixed therewith, as has tion, of; spring 35 toperiodlcallypermit the re-- lease; of: the; steam containedirr. theupper part of the, drum., The steam escapesthrough valve 23,,cond'uit 22- and the opening 2| to the condenser 24 from which it may be withdrawncand disposed of.

After this preliminary operation is completed, the temperature of the mixture within the drum may be raisedxto a. point sufficient to drive off the lighter: volatile, components, such as, for-instance, thelight oilswhich are mixed with the lubricating oil. Under ordinary circumstances, it is preferable to raise the temperature of the mixture to about 550 F. whereat the pressure is approximately pounds per square inch before the screw 43 is actuated to permit the periodic release of these vapors. When the desired temperature-and pressurezhavebeen reached, the cam 31 is moved into operative position so that the. vapors are released at the end of each oscillation and. permitted to escape into the condenserrZlt from which they, may be collected and disposed of in. any desired manner;

It is often preferable tov continue thefractioning until at least one out of, lubricating oil is taken. In this case, after the lighter volatile vapors have been withdrawn, the cam 31 is again released to its inoperative position and the temperature within the drum 8 increased to such an extent that a. light lubricating component is vaporized; The temperature necessary for this vaporization is generally, between 700 and 750 F. which when attained will'be indicated by the pyrometer 32, so thatv an attendant may then move the cam 31 into its. operative position to permittheperiodicescape of the vapors-present within the still. As a matter of precaution, it is usually desirable-to take one cut of lubricating oil in order to insure the removal of all lighter component vapors.

In'accord'ance with this process and with the use ofthe rotating still hereinbefore described, it is possible toraise the temperature of the mixture within the still from ordinary room temperature up to substantially750 F; within a substantially short time, such as, for instance, thirty-five or forty minutes. It is believed that the presence of the fullers earth and the agitation thereof contribute considerably to the rapidity of this heating operation, since it isapparent that the fullers earth acts as a conductor by which heat from the walls of" the drum is readily conducted to the interior of the body of oil contained in the drum, and since it is apparent that during movement of the drum the angle irons l9 are effective to continuously agitate and churn the mixture therewithin, the heat is rapidly distributed throughout. the body of the mixture so that a rapid rise of temperature is made possible.

After the desired number of components have been vaporized and released through the valve 23, the drum may be stopped in the position shown in Figure 1, wherein the valve 25 is disposed inlalinement with the union 29 on conduit 26.. Connection is then made between the. union 29 and. the valve 25', ,so that the valve 2'5 may be opened to permit the mixture within the drum, which includes those components below the lubricating base andthe fullers earth, to run out and into the cooler 21. The cooler 21 is preferably of such size that the mixture from the drum 8 will bereadily cooled down to approximately 240? F. while passing therethrough. Fromthe cooler 27, the mixture proceeds throughconduit 52 to pump 53. The pump 53 operates to force the mixture through conduit 54 to filter press 55, which, as hereinbefore pointed out, is of the usual bag type. The pressure of the pump 53 builds up on the oil contained in the chamber of the filter press 55 and forces the oil through the filter bags, thereby extracting the fullers earth and the chemicals which were theretofore contained. The reclaimed, purified oil of natural color is then withdrawn from the conduit 51 and may be disposed of as is desired.

The series of operations may then be repeated after a new supply of acid treated and neutralized oil from the tank I is supplied to the drum 8.

From the foregoing description, it is apparent that the invention is susceptible of many modifications which will not depart from the spirit thereof, and, accordingly, it is to be distinctly understood that the foregoing description and the illustrations in the accompanying drawing are merely for the purpose of exemplifying one embodiment of this invention, and that various changes may be made in the details thereof without departing from the spirit of this invention. Furthermore, it is to be distinctly understood that such modifications and the use of individual features or sub-combinations of features which may be of utility are, although not specifically described herein, contemplated by and within the scope of the appended claims.

Having thus described the invention, what is claimed is:

1. In theart of reclaiming used lubricating oil containing moisture and low boiling hydrocarbon fractions the process which includes, confining a body of the oil in a restricted zone, which includes considerable vapor space, raising the temperature above the atmospheric boiling point of the moisture and light fractions, while maintaining the pressure unreleased, intermittently partially releasing the pressure and ultimately releasing it to around the atmospheric after such elevated temperature and pressure has been reached, and continuing said heating and intermittent release of pressure until the oil is freed of moisture and low boiling constituents.

2. In the art of reclaiming used lubricating oil containing moisture and low boiling hydrocarbon fractions the process which includes, confining a body of the oil in a restricted zone, which includes considerable vapor space, raising the temperature above the boiling point of the moisture and light fractions at a predetermined pressure above atmospheric, while maintaining the pressure unreleased, intermittently releasing the pressure to around predetermined pressure after such elevated temperature and pressure has been reached, and continuing said heating and intermittent release of pressure until the oil is freed of moisture and low boiling constituents.

3. In the art of reclaiming used lubricating oil containing moisture and low boiling hydrocarbon fractions the process which includes, confining a body of the oil in a restricted zone,

which includes considerable vapor space, raising the temperature to at least about 350 F. while maintaining the pressure unreleased, intermittently releasing the pressure after such elevated temperature and pressure have been reached, and continuing said heating and intermittent release of pressure until the oil is freed of moisture and low boiling constituents.

4. In the art of reclaiming used lubricating oil containing moisture and low boiling hydrocarbon fractions the process which includes, confining a body of the oil in a restricted zone, which includes considerable vapor space, raising the temperature above the atmospheric boiling point of the moisture and light fractions, while maintaining the pressure unreleased, intermittently releasing the pressure after such elevated temperature and pressure has been reached, raising the temperature above the atmospheric boiling point of a low boiling lubricating component While the pressure is unreleased, and intermittently releasing the pressure after such elevated temperature is reached.

FREDERICK G. BAENDER.

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